MongoCursor::explain
Return an explanation of the query, often useful for optimization and debugging
&reftitle.description;
public arrayMongoCursor::explain
&reftitle.parameters;
&no.function.parameters;
&reftitle.returnvalues;
Returns an explanation of the query.
&reftitle.examples;
<function>MongoCursor::explain</function> example
find(array("x"=>1), array("y"));
$cursor->sort(array("z" => 1))->limit(4)->skip(5);
var_dump($cursor->explain());
?>
]]>
&example.outputs.similar;
string(15) "BtreeCursor x_1"
["startKey"]=>
array(1) {
["x"]=>
int(1)
}
["endKey"]=>
array(1) {
["x"]=>
int(1)
}
["nscanned"]=>
float(4)
["n"]=>
int(4)
["scanAndOrder"]=>
int(1)
["millis"]=>
int(3)
["allPlans"]=>
array(2) {
[0]=>
array(3) {
["cursor"]=>
string(15) "BtreeCursor x_1"
["startKey"]=>
array(1) {
["x"]=>
int(1)
}
["endKey"]=>
array(1) {
["x"]=>
int(1)
}
}
[1]=>
array(3) {
["cursor"]=>
string(11) "BasicCursor"
["startKey"]=>
array(0) {
}
["endKey"]=>
array(0) {
}
}
}
}
]]>
&reftitle.errors;
Throws MongoConnectionException if it cannot reach the
database.
&reftitle.seealso;
MongoDB core docs on explain.